Stereochemical aspects of cyclophosphamide (CP) metabolism will be studied by use of synthetically prepared enantiomerically pure samples of 4-hydroperoxycyclophosphamide, 4-ketocyclophosphamide, and carboxyphosphamide. Enantiomeric (optical) purities of these chiral materials will be established by means of nuclear magnetic resonance techniques. Extension of these studies to the related anticancer compound isophosphamide (IP) will be pursued by the synthesis of (plus)-and (minus)-IP.